From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5CAF21AED49; Fri, 13 Sep 2024 03:55:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.10 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726199702; cv=none; b=XgbN6Ei5ptuGtN6/tJWCPwe2rdAN8nCw18wRgpU9wJzKqxYem6nXrCFU9+YJnAYiJunW+I8DnbZP6YrlLuUFxbQ5t/MBUyj/54cq0k43m64rE2Q/0YtA0QZ07+zGmHgLxpw43tl1Iyad6wTvQzinAgQmx4HZhSBq91Wpk7toFnE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726199702; c=relaxed/simple; bh=x+iVIu+R8bVjJ0KOFX55GeWTxdccM9M3Q2qzG1lmGpM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=tOG2gadAK0ZZv7+upeH+zh0yblzHFMNqm3i8Ut7yRpWzH3aEsLJYsyjfjLd/bcp11SsGNj4Idgu73Vggpr6RzHrhWCVRhgVh/hDJ3zxKLY+p1XJFDgdv/BDGIA1S6iRQo/OmpKTx10FjYjvoXee9oUS9n5hMITeZ/H7GfzLEUx0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=DpB5Svfp; arc=none smtp.client-ip=192.198.163.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="DpB5Svfp" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1726199701; x=1757735701; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=x+iVIu+R8bVjJ0KOFX55GeWTxdccM9M3Q2qzG1lmGpM=; b=DpB5SvfpeVwLoohWIc7HyC9cSHzEnq4P78FrimfLnimy5yq8Hvau8UEN xpNUfk3A73JRsiJljTOFuODogXyRBJ954cCY/lPSh3+7R6ldTeiZPNb+q u37AkRVuPlAZl3Q3VX7PT9Mdv5wAcq9qYfBbLNmtCZKZBsG0tp2jk2ChR L6AtgCt7T56rHW8b7y0VOz4O2cNSsBV7dc+9yuTAOnig4UjAOV5bdE49M 0ZSvn9CqK1aeyXobPeY2BQ0xQT43NbIcc/mtlN+US+Pz0gYBj++9XPT9m vp+GpZazLeSsQUadE4Y3OcVgXpym3c9VGpjsf+4XH3J5ge82pE+n/wVhQ w==; X-CSE-ConnectionGUID: kSLe/KxATPGRE9FOl98g8Q== X-CSE-MsgGUID: Ayihkq+YS32EVP+ZoBoPUA== X-IronPort-AV: E=McAfee;i="6700,10204,11193"; a="36466598" X-IronPort-AV: E=Sophos;i="6.10,224,1719903600"; d="scan'208";a="36466598" Received: from orviesa008.jf.intel.com ([10.64.159.148]) by fmvoesa104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Sep 2024 20:55:00 -0700 X-CSE-ConnectionGUID: CkpM+50KTxuronlFsPj+Iw== X-CSE-MsgGUID: CS2zJcFbTvaAXCLEXysEZQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.10,224,1719903600"; d="scan'208";a="68698681" Received: from xiaoyaol-hp-g830.ccr.corp.intel.com (HELO [10.124.224.38]) ([10.124.224.38]) by orviesa008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Sep 2024 20:54:59 -0700 Message-ID: <36289f8c-85e1-4bb9-aff3-648ead059cd0@intel.com> Date: Fri, 13 Sep 2024 11:54:55 +0800 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 25/25] KVM: x86: Add CPUID bits missing from KVM_GET_SUPPORTED_CPUID To: Sean Christopherson , Paolo Bonzini Cc: Rick Edgecombe , kvm@vger.kernel.org, kai.huang@intel.com, isaku.yamahata@gmail.com, tony.lindgren@linux.intel.com, linux-kernel@vger.kernel.org References: <20240812224820.34826-1-rick.p.edgecombe@intel.com> <20240812224820.34826-26-rick.p.edgecombe@intel.com> <05cf3e20-6508-48c3-9e4c-9f2a2a719012@redhat.com> Content-Language: en-US From: Xiaoyao Li In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 9/13/2024 2:41 AM, Sean Christopherson wrote: >>> CET might be a bad example because it looks like it's controlled by TDCS.XFAM, but >>> presumably there are other CPUID-based features that would actively enable some >>> feature for a TDX VM. >> XFAM is controlled by userspace though, not KVM, so we've got no >> control on that either. > I assume it's plain text though? I.e. whatever ioctl() sets TDCS.XFAM can be > rejected by KVM if it attempts to enable unsupported features? yes. XFAM is validated by KVM actually in this series. KVM reports supported_xfam via KVM_TDX_CAPABILITIES and userspace sets XFAM via ioctl(KVM_TDX_VM_INIT). If userspace sets any bits beyond the supported_xfam, KVM returns -EINVAL. The same for attributes. > I don't expect that we'll want KVM to gatekeep many, if any features, but I do > think we should require explicit enabling in KVM whenever possible, even if the > enabling is boring and largely ceremonial. +1